Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 10 Jul 2018 16:47:36 -0400
From:   Sean Paul <seanpaul@chromium.org>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Rob Clark <robdclark@gmail.com>, David Airlie <airlied@linux.ie>,
        y2038@lists.linaro.org, Jordan Crouse <jcrouse@codeaurora.org>,
        Sean Paul <seanpaul@chromium.org>,
        linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/msm: avoid using 'timespec'
Message-ID: <20180710204736.GU20303@art_vandelay>
References: <20180618153959.2169325-1-arnd@arndb.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180618153959.2169325-1-arnd@arndb.de>
User-Agent: Mutt/1.9.2 (2017-12-15)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Jun 18, 2018 at 05:39:42PM +0200, Arnd Bergmann wrote:
> The timespec structure and associated interfaces are deprecated and will
> be removed in the future because of the y2038 overflow.
> 
> The use of ktime_to_timespec() in timeout_to_jiffies() does not
> suffer from that overflow, but is easy to avoid by just converting
> the ktime_t into jiffies directly.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/gpu/drm/msm/msm_drv.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> index b2da1fbf81e0..cc8977476a41 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -353,8 +353,7 @@ static inline unsigned long timeout_to_jiffies(const ktime_t *timeout)
>  		remaining_jiffies = 0;
>  	} else {
>  		ktime_t rem = ktime_sub(*timeout, now);
> -		struct timespec ts = ktime_to_timespec(rem);
> -		remaining_jiffies = timespec_to_jiffies(&ts);
> +		remaining_jiffies = ktime_divns(rem, NSEC_PER_SEC / HZ);

Do you need to wrap rem in ktime_to_ns() just to be safe?

Sean

>  	}
>  
>  	return remaining_jiffies;
> -- 
> 2.9.0
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS